1. Field of the Invention
The present invention relates to an ink jet recording head in which a piezoelectric vibration plate is stuck to a part of a pressure generating chamber communicating with nozzle openings, and a deflection vibration of the piezoelectric vibrating plate compresses the pressure generating chamber to generate ink droplets.
2. Related Art
In the known ink jet recording head, a piezoelectric vibration plate is stuck onto an elastic plate as a part of the pressure generating chamber in a stretched fashion. By a deflection vibration of the piezoelectric vibration plate, the volume of the pressure generating chamber is varied to cause ink droplets. In this ink jet recording head, the pressure chamber can be compressed and expanded over a broad area thereof, so that ink droplets can be forcibly discharged from the nozzle openings thereof.
In the construction of the piezoelectric vibration plate assembled into the ink jet recording head, small thin layers made of piezoelectric material are arrayed on an elastic plate. Electrodes are layered on both sides of the resultant structure. In operation, a drive signal is applied to the electrodes, to thereby deflect the resultant piezoelectric vibration plate in a vibration mode.
To efficiently transfer a deflection vibration of the piezoelectric vibration plate to the elastic plate, it is necessary to reliably bond the reverse side of the piezoelectric vibration plate onto the elastic plate.
A novel technique to improve the bonding of the piezoelectric vibration plate to a substrate is disclosed in Japanese Patent Laid-Open Publication No. Hei. 5-267742. A drive electrode made of conductive material having a satisfactory bonding force is formed on the drive electrode area of the elastic plate onto which the piezoelectric vibration plate is attached, during a process of sintering a piezoelectric material. A lead-out electrode led from a common electrode, which is made of the same material as of the drive electrode, is formed also in the area, which does not directly contribute to the piezoelectric vibration. For the piezoelectric vibration plate, the tips of the piezoelectric vibration plates partially overlap on the lead-out electrode led from the common electrode, thereby increasing the bonding force of the piezoelectric vibration plates and the substrate.
This technique considerably increases the bonding force of the plate member and the piezoelectric vibration plates. However, where the piezoelectric vibration plates are reduced in size, a problem arises, viz., the contact areas of the piezoelectric vibration plates and the lead-out electrode for the common electrode are not uniform in size. As a result, the tip A of the piezoelectric vibration plate is raised from the lead-out electrode B for the common electrode, as shown in FIG. 10. The bonding force of the piezoelectric vibration plates and the substrate is weakened. A connection point D of the common electrode C formed on the upper surface and the lead-out electrode B is thinned in thickness.